New insights into the cognitive effects of sleep deprivation by decomposition of a cognitive throughput task

Abstract

Study Objectives A cognitive throughput task known as the Digit Symbol Substitution Test (DSST) (or Symbol Digit Modalities Test) has been used as an assay of general cognitive slowing during sleep deprivation. Here, the effects of total sleep deprivation (TSD) on specific cognitive processes involved in DSST performance, including visual search, spatial memory, paired-associate learning, and motor response, were investigated through targeted task manipulations. Methods A total of 12 DSST variants, designed to manipulate the use of specific cognitive processes, were implemented in two laboratory-based TSD studies with N = 59 and N = 26 subjects, respectively. In each study, the Psychomotor Vigilance Test (PVT) was administered alongside the DSST variants. Results TSD reduced cognitive throughput on all DSST variants, with response time distributions exhibiting rightward skewing. All DSST variants showed practice effects, which were however minimized by inclusion of a pause between trials. Importantly, TSD-induced impairment on the DSST variants was not uniform, with a principal component analysis revealing three factors. Diffusion model decomposition of cognitive processes revealed that inter-individual differences during TSD on a two-alternative forced choice DSST variant were different from those on the PVT. Conclusions While reduced cognitive throughput has been interpreted to reflect general cognitive slowing, such TSD-induced impairment appears to reflect cognitive instability, like on the PVT, rather than general slowing. Further, comparisons between task variants revealed not one, but three distinct underlying processes impacted by sleep deprivation. Moreover, the practice effect on the task was found to be independent of the TSD effect and minimized by a task pacing manipulation.

Total Sleep Deprivation Impairs Lateralization of Spatial Working Memory in Young Men

“…For example, increased P3 latency is associated with impaired discernment of target stimuli ( Kutas et al, 1977 ). Therefore, we believe that 36-h TSD impairs the individual’s spatial working memory ability by affecting the allocation of attention resources, and the individual has a reaction disorder to the change in information ( Chua et al, 2014 ; Honn et al, 2020 ; Skurvydas et al, 2020 ). Under baseline conditions, P3 amplitude was significantly greater in the right hemisphere than in the left.…”

Working around the Clock: Is a Person’s Endogenous Circadian Timing for Optimal Neurobehavioral Functioning Inherently Task-Dependent?

“…The task shows a minor but persistent practice effect [ 45 ]; however, at the start of the CR protocol the practice effect would have approached asymptote as, by that time, subjects had already performed the task more than two dozen times across the simulated shift work days. The components of cognition involved in the DSST are partially distinct from those involved in the PVT [ 40 ], and DSST performance has been shown to be functionally distinct from PVT performance both within [ 45 ] and between [ 36 ] individuals.…”

“…Various other potential confounds further cast doubt on the reliability of reports of task-specificity in the timing of circadian rhythms [ 34 ]. That is, different performance tasks are differentially susceptible to phenomena that can mask circadian rhythmicity, including practice effects [ 40 ], performance strategy changes [ 41 ], and temporal changes in speed/accuracy trade-offs [ 42 ]. These masking effects could create the appearance of task-dependent differences in the effect of circadian rhythmicity on neurobehavioral functioning even when no such differences are endogenously produced.…”

“…The CR protocol served to measure neurobehavioral functioning, at 2 h intervals, under strictly controlled conditions, and to expose the endogenous circadian rhythmicity [ 43 ]. The neurobehavioral assays we used were functionally distinct [ 36 , 40 ], suitable for repeated administration, and not subject to masking from practice, strategy changes, or dynamically shifting speed/accuracy trade-offs. The test battery included a psychomotor vigilance test (PVT) [ 44 ], a computerized digit symbol substitution test (DSST) [ 45 ], and the Karolinska Sleepiness Scale (KSS) [ 46 ].…”

Floor vibrations for motivation and feedback in the rat vibration actuating search task

“…Performance feedback is often used in tests of human cognition in the context of impairment due to SD, such as paired associates learning [ 17 , 18 ], task rule or goal switching [ 19 , 20 ], or cognitive flexibility [ 21 – 23 ]. Sleep loss produces considerable deficits in decision making that requires the use of outcome feedback to monitor and adapt one’s own performance [ 24 ], although the underlying mechanisms are subject to investigation and debate [ 25 – 27 ].…”